“Sopranos” actor Louis Gross pleaded not guilty to eight counts of criminal possession of a forged instrument in the first degree, a felony that could land him behind bars for up to 15 years. Photo: Steven Hirsch

If only Tony Soprano were still around.

Appearing in court Monday to face forgery charges, an actor who briefly played the mob boss’ driver on the “The Sopranos,” recalled with fondness how the late James Gandolfini tried to help his career.

“I did knucklehead things,” said Louis Gross, 31, who played Perry Annunziata.

Late “Sopranos” boss James Gandolfini in a scene with Louis Gross.

“I showed up late a few times and he went out of his way to make sure they didn’t fire me,” said Gross, who pleaded not guilty in Manhattan Supreme Court to eight counts of criminal possession of a forged instrument in the first degree, a felony that could land him behind bars for up to 15 years.

Gross was busted in August with eight phony $100 bills after he allegedly tried to buy a burger with fake cash at a Third Avenue bar.

“I’m only doing this because my girlfriend is sick,” he allegedly told cops. He said he’d bought the cash from “a guy in Queens,” according to court papers released Monday.

The bad-boy actor, whose character was nicknamed “Muscles Marinara” by Soprano on the show, changed his story when he spoke to reporters Monday as he left the courthouse.

Gross sold an Enduro mountain bike for $2,000 on Craigslist and unwittingly received the fake bills, he claimed.

“I ordered a hamburger and went to pay at the bar,” he explained. “When the owner came out, he said this is fake. I said I’m really sorry and started walking down the block and the police jumped out.”

Of Gandolfini, he said, “He was one of the best people I met in the industry.”